Distinguishing Winter Blahs from SAD

THE DAYS are fast becoming shorter and darker, signaling winter doldrums for many. But if your fall and winter days are worse than blah--if depression becomes severe enough that it's difficult to maintain your work schedule, concentrate effectively, sleep well, and sustain interest in social activities--you may suffer from Seasonal Affective Disorder, or SAD, experienced yearly by an estimated 10 million Americans. Other aspects of the SAD pattern, which must occur for two or more consecutive winters for an official diagnosis: sluggishness, irritability, and increased cravings for alcohol and carbohydrates, including sweets. Of course, the carbohydrate cravings, coupled with the SAD tendency for inactivity during winter, tend to result in weight gain, which can heighten feelings of despair.

Changes in two critical brain chemicals are believed to trigger the appetite shift and other SAD characteristics:

Serotonin When a mood-regulating neurotransmitter called serotonin dips to very low levels, as it does in people with SAD, depression occurs. Carbohydrates stimulate the production of serotonin, so some scientists have speculated that the carbohydrate cravings common to people with SAD may be the body's way of working to raise serotonin concentrations. Indeed, research has suggested that people with SAD feel energized after a carbohydrate-rich meal, while those without the condition often report feeling sluggish after a high-carb meal such as pasta.

Melatonin Melatonin is a brain chemical that triggers sleep, and recent research conducted by investigators at the National Institute of Mental Health has indicated that people with SAD produce more of it in winter than in summer. That may help to explain why SAD sufferers tend to oversleep and "hibernate" in winter.

Despite these discoveries, and despite the fact that SAD has been around a long time (even Hippocrates noted the condition more than 2,000 years ago), the exact cause is still not well understood. Many researchers believe that genetics as well as environmental influences play a role. Consider that the condition is commonly found in geographic areas that are furthest from the Equator and therefore receive less sunlight.

The good news is that while scientists continue to try to nail down SAD's underpinnings, they do seem to have come up with a fairly good treatment: light therapy. Apparently, bright light helps suppress the brain's secretion of melatonin, thereby resetting the body's sleep/wake cycles.

Whatever the mechanism, numerous studies have shown that people can dramatically improve or even eliminate their SAD symptoms by spending 30 minutes to 2 hours daily in front of a specially designed light-emitting apparatus. There are numerous light therapy products on the market, ranging from portable light boxes to lamps, even visors worn on the head. Most devices emit 5,000 to 10,000 lux (units of intensity) of light (from which ultraviolet rays have been filtered). That makes them five to 20 times as bright as the bulbs in your home lighting.

Response rate varies, but most people report improvement in symptoms within 2 to 5 days of starting treatment. It is generally recommended that treatment begin in the early fall, as soon as the first symptoms of SAD appear; some doctors suggest beginning treatment even earlier.

Note that prices for light therapy products tend to range from about $150 to $280, but the cost may be covered by some insurance plans.

Those for whom light therapy isn't enough by itself often find it works in combination with antidepressants. The ones most commonly used are selective serotonin reuptake inhibitors (SSRIs), such as Prozac and Paxil. They operate by slowing transmission of serotonin, thereby allowing the body to maximize the effect of the reduced amount of serotonin available.

Before assuming you need treatment, consult with your doctor. SAD is a diagnosable mental disorder, not simply a case of the winter blues, and a health professional is needed to make the distinction.

For more information, contact the National Mental Health Association, 2001 N. Beauregard Street, 12th floor, Alexandria, VA 22311; (800) 969-6642. Or take a look at a copy of Winter Blues: Seasonal Affective Disorder--What It Is and How To Treat It, by Norman Rosenthal, MD (Guilford Press: New York, 1998.) Dr. Rosenthal is the researcher credited with identifying and naming SAD.